Nand data placement schema

ABSTRACT

Disclosed in some examples are improvements to data placement architectures in NAND that provide additional data protection through an improved NAND data placement schema that allows for recovery from certain failure scenarios. The present disclosure stripes data diagonally across page lines and planes to enhance the data protection. Parity bits are stored in SLC blocks for extra protection until the block is finished writing and then the parity bits may be deleted.

PRIORITY APPLICATIONS

The current application claims the benefit of priority to U.S.Provisional Application Ser. No. 62/675,451, filed May 23, 2018 and toU.S. Provisional Application Ser. No. 62/644,248, filed Mar. 16, 2018,both of which are incorporated herein by reference in their entireties.

BACKGROUND

Memory devices are typically provided as internal, semiconductor,integrated circuits in computers or other electronic devices. There aremany different types of memory, including volatile and non-volatilememory.

Volatile memory requires power to maintain its data, and includesrandom-access memory (RAM), dynamic random-access memory (DRAM), orsynchronous dynamic random-access memory (SDRAM), among others.

Non-volatile memory can retain stored data when not powered, andincludes flash memory, read-only memory (ROM), electrically erasableprogrammable ROM (EEPROM), static RAM (SRAM), erasable programmable ROM(EPROM), resistance variable memory, such as phase-change random-accessmemory (PCRAM), resistive random-access memory (RRAM), magnetoresistiverandom-access memory (MRAM), or 3D XPoint™ memory, among others.

Flash memory is utilized as non-volatile memory for a wide range ofelectronic applications. Flash memory devices typically include one ormore groups of one-transistor, floating gate or charge trap memory cellsthat allow for high memory densities, high reliability, and low powerconsumption.

Two common types of flash memory array architectures include NAND andNOR architectures, named after the logic form in which the basic memorycell configuration of each is arranged. The memory cells of the memoryarray are typically arranged in a matrix. In an example, the gates ofeach floating gate memory cell in a row of the array are coupled to anaccess line (e.g., a word line). In a NOR architecture, the drains ofeach memory cell in a column of the array are coupled to a data line(e.g., a bit line). In a NAND architecture, the drains of each memorycell in a string of the array are coupled together in series, source todrain, between a source line and a bit line.

Both NOR and NAND architecture semiconductor memory arrays are accessedthrough decoders that activate specific memory cells by selecting theword line coupled to their gates. In a NOR architecture semiconductormemory array, once activated, the selected memory cells place their datavalues on bit lines, causing different currents to flow depending on thestate at which a particular cell is programmed. In a NAND architecturesemiconductor memory array, a high bias voltage is applied to adrain-side select gate (SGD) line. Word lines coupled to the gates ofthe unselected memory cells of each group are driven at a specified passvoltage (e.g., Vpass) to operate the unselected memory cells of eachgroup as pass transistors (e.g., to pass current in a mannerunrestricted by their stored data values). Current then flows from thesource line to the bit line through each series coupled group,restricted only by the selected memory cells of each group, placingcurrent encoded data values of selected memory cells on the bit lines.

Each flash memory cell in a NOR or NAND architecture semiconductormemory array can be programmed individually or collectively to one or anumber of programmed states. For example, a single-level cell (SLC) canrepresent one of two programmed states (e.g., 1 or 0), representing onebit of data.

However, flash memory cells can also represent one of more than twoprogrammed states, allowing the manufacture of higher density memorieswithout increasing the number of memory cells, as each cell canrepresent more than one binary digit (e.g., more than one bit). Suchcells can be referred to as multi-state memory cells, multi-digit cells,or multi-level cells (MLCs). In certain examples, MLC can refer to amemory cell that can store two bits of data per cell (e.g., one of fourprogrammed states), a triple-level cell (TLC) can refer to a memory cellthat can store three bits of data per cell (e.g., one of eightprogrammed states), and a quad-level cell (QLC) can store four bits ofdata per cell. MLC is used herein in its broader context, to can referto any memory cell that can store more than one bit of data per cell(i.e., that can represent more than two programmed states).

Traditional memory arrays are two-dimensional (2D) structures arrangedon a surface of a semiconductor substrate. To increase memory capacityfor a given area, and to decrease cost, the size of the individualmemory cells has decreased. However, there is a technological limit tothe reduction in size of the individual memory cells, and thus, to thememory density of 2D memory arrays. In response, three-dimensional (3D)memory structures, such as 3D NAND architecture semiconductor memorydevices, are being developed to further increase memory density andlower memory cost.

Such 3D NAND devices often include strings of storage cells, coupled inseries (e.g., drain to source), between one or more source-side selectgates (SGSs) proximate a source, and one or more drain-side select gates(SGDs) proximate a bit line. In an example, the SGSs or the SGDs caninclude one or more field-effect transistors (FETs) or metal-oxidesemiconductor (MOS) structure devices, etc. In some examples, thestrings will extend vertically, through multiple vertically spaced tierscontaining respective word lines. A semiconductor structure (e.g., apolysilicon structure) may extend adjacent a string of storage cells toform a channel for the storages cells of the string. In the example of avertical string, the polysilicon structure may be in the form of avertically extending pillar. In some examples the string may be“folded,” and thus arranged relative to a U-shaped pillar. In otherexamples, multiple vertical structures may be stacked upon one anotherto form stacked arrays of storage cell strings.

Memory arrays or devices can be combined together to form a storagevolume of a memory system, such as a solid-state drive (SSD), aUniversal Flash Storage (UFS™) device, a MultiMediaCard (MMC)solid-state storage device, an embedded MMC device (eMMC™), etc. An SSDcan be used as, among other things, the main storage device of acomputer, having advantages over traditional hard drives with movingparts with respect to, for example, performance, size, weight,ruggedness, operating temperature range, and power consumption. Forexample, SSDs can have reduced seek time, latency, or other delayassociated with magnetic disk drives (e.g., electromechanical, etc.).SSDs use non-volatile memory cells, such as flash memory cells toobviate internal battery supply requirements, thus allowing the drive tobe more versatile and compact.

An SSD can include a number of memory devices, including a number ofdies or logical units (e.g., logical unit numbers or LUNs), and caninclude one or more processors or other controllers performing logicfunctions required to operate the memory devices or interface withexternal systems. Such SSDs may include one or more flash memory die,including a number of memory arrays and peripheral circuitry thereon.The flash memory arrays can include a number of blocks of memory cellsorganized into a number of physical pages. In many examples, the SSDswill also include DRAM or SRAM (or other forms of memory die or othermemory structures). The SSD can receive commands from a host inassociation with memory operations, such as read or write operations totransfer data (e.g., user data and associated integrity data, such aserror data and address data, etc.) between the memory devices and thehost, or erase operations to erase data from the memory devices.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 illustrates an example of an environment including a memorydevice.

FIGS. 2-3 illustrate schematic diagrams of an example of a 3D NANDarchitecture semiconductor memory array.

FIG. 4 illustrates an example block diagram of a memory module.

FIG. 5 illustrates possible effects of a programming failure of a NAND.

FIG. 6 illustrates possible effects an asynchronous power loss duringprogramming of a NAND.

FIGS. 7 and 8 illustrate an improved NAND data placement schema of dataon a TLC NAND array according to some examples of the presentdisclosure.

FIG. 9 illustrates a logical placement of the parity pages in a volatilememory of the controller or other component of the NAND according tosome examples of the present disclosure.

FIG. 10 illustrates a schematic of a parity value storage used to storethe parity pages in nonvolatile NAND.

FIG. 11 illustrates a flowchart of a method 1100 of applying an improvedNAND data placement schema to storing data on a NAND die of a NANDdevice according to some examples of the present disclosure.

FIG. 12 illustrates an example of an uncorrectable error of a NANDaccording to some examples of the present disclosure.

FIG. 13 illustrates storage of a plurality of parity values that arearranged in a plurality of clusters according to some examples of thepresent disclosure.

FIG. 14 illustrates storage of a plurality of compressed parity valuesaccording to some examples of the present disclosure.

FIG. 15 illustrates a flow chart of a method of clustering parity valuesin an improved NAND data placement schema of a NAND device according tosome examples of the present disclosure.

FIG. 16 illustrates a schematic of a memory controller according to someexamples of the present disclosure.

FIG. 17 is a block diagram illustrating an example of a machine uponwhich one or more embodiments may be implemented.

DETAILED DESCRIPTION

Disclosed in some examples are methods of organizing data written to amemory device (such as a NAND memory device) in order to protect againstcertain types of faults. For example, a first portion is programmed on afirst page line and a first plane, a second portion is programmed on asecond page line and a second plane, a third portion is programmed on athird page line and a third plane, and a fourth portion is programmed ona fourth page line and a fourth plane. The first page line, second pageline, third page line, first plane, second plane, and third plane areselected such that the first portion, second portion and third portionare stored in memory cells that are on different page lines anddifferent planes with respect to each other.

Electronic devices, such as mobile electronic devices (e.g., smartphones, tablets, etc.), electronic devices for use in automotiveapplications (e.g., automotive sensors, control units, driver-assistancesystems, passenger safety or comfort systems, etc.), andinternet-connected appliances or devices (e.g., internet-of-things (IoT)devices, etc.), have varying storage needs depending on, among otherthings, the type of electronic device, use environment, performanceexpectations, etc.

Electronic devices can be broken down into several main components: aprocessor (e.g., a central processing unit (CPU) or other mainprocessor); memory (e.g., one or more volatile or non-volatilerandom-access memory (RAM) memory device, such as dynamic RAM (DRAM),mobile or low-power double-data-rate synchronous DRAM (DDR SDRAM),etc.); and a storage device (e.g., non-volatile memory (NVM) device,such as flash memory, read-only memory (ROM), an SSD, an MMC, or othermemory card structure or assembly, etc.). In certain examples,electronic devices can include a user interface (e.g., a display,touch-screen, keyboard, one or more buttons, etc.), a graphicsprocessing unit (GPU), a power management circuit, a baseband processoror one or more transceiver circuits, etc.

FIG. 1 illustrates an example of an environment 100 including a hostdevice 105 and a memory device 110 configured to communicate over acommunication interface. The host device 105 or the memory device 110may be included in a variety of products 150, such as Internet of Things(IoT) devices (e.g., a refrigerator or other appliance, sensor, motor oractuator, mobile communication device, automobile, drone, etc.) tosupport processing, communications, or control of the product 150.

The memory device 110 includes a memory controller 115 and a memoryarray 120 including, for example, a number of individual memory die(e.g., a stack of three-dimensional (3D) NAND die). In 3D architecturesemiconductor memory technology, vertical structures are stacked,increasing the number of tiers, physical pages, and accordingly, thedensity of a memory device (e.g., a storage device). In an example, thememory device 110 can be a discrete memory or storage device componentof the host device 105. In other examples, the memory device 110 can bea portion of an integrated circuit (e.g., system on a chip (SOC), etc.),stacked or otherwise included with one or more other components of thehost device 105.

One or more communication interfaces can be used to transfer databetween the memory device 110 and one or more other components of thehost device 105, such as a Serial Advanced Technology Attachment (SATA)interface, a Peripheral Component Interconnect Express (PCIe) interface,a Universal Serial Bus (USB) interface, a Universal Flash Storage (UFS)interface, an eMMC™ interface, or one or more other connectors orinterfaces. The host device 105 can include a host system, an electronicdevice, a processor, a memory card reader, or one or more otherelectronic devices external to the memory device 110. In some examples,the host 105 may be a machine having some portion, or all, of thecomponents discussed in reference to the machine 1700 of FIG. 17.

The memory controller 115 can receive instructions from the host 105,and can communicate with the memory array, such as to transfer data to(e.g., write or erase) or from (e.g., read) one or more of the memorycells, planes, sub-blocks, blocks, or pages of the memory array. Thememory controller 115 can include, among other things, circuitry orfirmware, including one or more components or integrated circuits. Forexample, the memory controller 115 can include one or more memorycontrol units, circuits, or components configured to control accessacross the memory array 120 and to provide a translation layer betweenthe host 105 and the memory device 110. The memory controller 115 caninclude one or more input/output (I/O) circuits, lines, or interfaces totransfer data to or from the memory array 120. The memory controller 115can include a memory manager 125 and an array controller 135.

The memory manager 125 can include, among other things, circuitry orfirmware, such as a number of components or integrated circuitsassociated with various memory management functions. For purposes of thepresent description example memory operation and management functionswill be described in the context of NAND memory. Persons skilled in theart will recognize that other forms of non-volatile memory may haveanalogous memory operations or management functions. Such NANDmanagement functions include wear leveling (e.g., garbage collection orreclamation), error detection or correction, block retirement, or one ormore other memory management functions. The memory manager 125 can parseor format host commands (e.g., commands received from a host) intodevice commands (e.g., commands associated with operation of a memoryarray, etc.), or generate device commands (e.g., to accomplish variousmemory management functions) for the array controller 135 or one or moreother components of the memory device 110.

The memory manager 125 can include a set of management tables 130configured to maintain various information associated with one or morecomponent of the memory device 110 (e.g., various information associatedwith a memory array or one or more memory cells coupled to the memorycontroller 115). For example, the management tables 130 can includeinformation regarding block age, block erase count, error history, orone or more error counts (e.g., a write operation error count, a readbit error count, a read operation error count, an erase error count,etc.) for one or more blocks of memory cells coupled to the memorycontroller 115. In certain examples, if the number of detected errorsfor one or more of the error counts is above a threshold, the bit errorcan be referred to as an uncorrectable bit error. The management tables130 can maintain a count of correctable or uncorrectable bit errors,among other things.

The array controller 135 can include, among other things, circuitry orcomponents configured to control memory operations associated withwriting data to, reading data from, or erasing one or more memory cellsof the memory device 110 coupled to the memory controller 115. Thememory operations can be based on, for example, host commands receivedfrom the host 105, or internally generated by the memory manager 125(e.g., in association with wear leveling, error detection or correction,etc.).

The array controller 135 can include an error correction code (ECC)component 140, which can include, among other things, an ECC engine orother circuitry configured to detect or correct errors associated withwriting data to or reading data from one or more memory cells of thememory device 110 coupled to the memory controller 115. The memorycontroller 115 can be configured to actively detect and recover fromerror occurrences (e.g., bit errors, operation errors, etc.) associatedwith various operations or storage of data, while maintaining integrityof the data transferred between the host 105 and the memory device 110,or maintaining integrity of stored data (e.g., using redundant RAIDstorage, etc.), and can remove (e.g., retire) failing memory resources(e.g., memory cells, memory arrays, pages, blocks, etc.) to preventfuture errors.

In some examples, the memory array may comprise a number of NAND diesand one or more functions of the memory controller 115 for a particularNAND die may be implemented on an on-die controller on that particulardie. Other organizations and delineations of control functionality mayalso be utilized, such as a controller for each die, plane, superblock,block, page, and the like.

The memory array 120 can include several memory cells arranged in, forexample, a number of devices, semi-conductor dies, planes, sub-blocks,blocks, or pages. As one example, a 48 GB TLC NAND memory device caninclude 18,592 bytes (B) of data per page (16,384+2208 bytes), 1536pages per block, 548 blocks per plane, and 4 or more planes per device.As another example, a 32 GB MLC memory device (storing two bits of dataper cell (i.e., 4 programmable states)) can include 18,592 bytes (B) ofdata per page (16,384+2208 bytes), 1024 pages per block, 548 blocks perplane, and 4 planes per device, but with half the required write timeand twice the program/erase (P/E) cycles as a corresponding TLC memorydevice. Other examples can include other numbers or arrangements. Insome examples, a memory device, or a portion thereof, may be selectivelyoperated in SLC mode, or in a desired MLC mode (such as TLC, QLC, etc.).

In operation, data is typically written to or read from the NAND memorydevice 110 in pages, and erased in blocks. However, one or more memoryoperations (e.g., read, write, erase, etc.) can be performed on largeror smaller groups of memory cells, as desired. The data transfer size ofa NAND memory device 110 is typically referred to as a page, whereas thedata transfer size of a host is typically referred to as a sector.

Although a page of data can include a number of bytes of user data(e.g., a data payload including a number of sectors of data) and itscorresponding metadata, the size of the page often refers only to thenumber of bytes used to store the user data. As an example, a page ofdata having a page size of 4 KB may include 4 KB of user data (e.g., 8sectors assuming a sector size of 512 B) as well as a number of bytes(e.g., 32 B, 54 B, 224 B, etc.) of metadata corresponding to the userdata, such as integrity data (e.g., error detecting or correcting codedata), address data (e.g., logical address data, etc.), or othermetadata associated with the user data.

Different types of memory cells or memory arrays 120 can provide fordifferent page sizes, or may require different amounts of metadataassociated therewith. For example, different memory device types mayhave different bit error rates, which can lead to different amounts ofmetadata necessary to ensure integrity of the page of data (e.g., amemory device with a higher bit error rate may require more bytes oferror correction code data than a memory device with a lower bit errorrate). As an example, a multi-level cell (MLC) NAND flash device mayhave a higher bit error rate than a corresponding single-level cell(SLC) NAND flash device. As such, the MLC device may require moremetadata bytes for error data than the corresponding SLC device.

FIG. 2 illustrates an example schematic diagram of a 3D NANDarchitecture semiconductor memory array 200 including a number ofstrings of memory cells (e.g., first-third A₀ memory strings205A₀-207A₀, first-third A_(n) memory strings 205A_(n)-207A_(n),first-third B₀ memory strings 205B₀-207B₀, first-third B_(n) memorystrings 205B_(n)-207B_(n), etc.), organized in blocks (e.g., block A201A, block B 201B, etc.) and sub-blocks (e.g., sub-block A₀ 201A₀,sub-block A_(n) 201A_(n), sub-block B₀ 201B₀, sub-block B_(n) 201B_(n),etc.). The memory array 200 represents a portion of a greater number ofsimilar structures that would typically be found in a block, device, orother unit of a memory device.

Each string of memory cells includes a number of tiers of charge storagetransistors (e.g., floating gate transistors, charge-trappingstructures, etc.) stacked in the Z direction, source to drain, between asource line (SRC) 235 or a source-side select gate (SGS) (e.g.,first-third A₀ SGS 231A₀-233A₀, first-third A_(n) SGS 231A_(n)-233A_(n),first-third B₀ SGS 231B₀-233B₀, first-third B_(n) SGS 231B_(n)-233B_(n),etc.) and a drain-side select gate (SGD) (e.g., first-third A₀ SGD226A₀-228A₀, first-third A_(n) SGD 226A_(n)-228A_(n), first-third B₀ SGD226B₀-228B₀, first-third B_(n) SGD 226B_(n)-228B_(n), etc.). Each stringof memory cells in the 3D memory array can be arranged along the Xdirection as data lines (e.g., bit lines (BL) BL0-BL2 220-222), andalong the Y direction as physical pages.

Within a physical page, each tier represents a row of memory cells, andeach string of memory cells represents a column. A sub-block can includeone or more physical pages. A block can include a number of sub-blocks(or physical pages) (e.g., 128, 256, 384, etc.). Although illustratedherein as having two blocks, each block having two sub-blocks, eachsub-block having a single physical page, each physical page having threestrings of memory cells, and each string having 8 tiers of memory cells,in other examples, the memory array 200 can include more or fewerblocks, sub-blocks, physical pages, strings of memory cells, memorycells, or tiers. For example, each string of memory cells can includemore or fewer tiers (e.g., 16, 32, 64, 128, etc.), as well as one ormore additional tiers of semiconductor material above or below thecharge storage transistors (e.g., select gates, data lines, etc.), asdesired. As an example, a 48 GB TLC NAND memory device can include18,592 bytes (B) of data per page (16,384+2208 bytes), 1536 pages perblock, 548 blocks per plane, and 4 or more planes per device.

Each memory cell in the memory array 200 includes a control gate (CG)coupled to (e.g., electrically or otherwise operatively connected to) anaccess line (e.g., word lines (WL) WL0 ₀-WL7 ₀ 210A-217A, WL0 ₁-WL7 ₁210B-217B, etc.), which collectively couples the control gates (CGs)across a specific tier, or a portion of a tier, as desired. Specifictiers in the 3D memory array, and accordingly, specific memory cells ina string, can be accessed or controlled using respective access lines.Groups of select gates can be accessed using various select lines. Forexample, first-third A₀ SGD 226A₀-228A₀ can be accessed using an A₀ SGDline SGDA₀ 225A₀, first-third A_(n) SGD 226A_(n)-228A_(n) can beaccessed using an A_(n) SGD line SGDA_(n) 225A_(n), first-third B₀ SGD226B₀-228B₀ can be accessed using an B₀ SGD line SGDB₀ 225B₀, andfirst-third B_(n) SGD 226B_(n)-228B_(n) can be accessed using an B_(n)SGD line SGDB_(n) 225B_(n). First-third A₀ SGS 231A₀-233A₀ andfirst-third A_(n) SGS 231A_(n)-233A_(n) can be accessed using a gateselect line SGS₀ 230A, and first-third B₀ SGS 231B₀-233B₀ andfirst-third B_(n) SGS 231B_(n)-233B_(n) can be accessed using a gateselect line SGS₁ 230B.

In an example, the memory array 200 can include a number of levels ofsemiconductor material (e.g., polysilicon, etc.) configured to couplethe control gates (CGs) of each memory cell or select gate (or a portionof the CGs or select gates) of a respective tier of the array. Specificstrings of memory cells in the array can be accessed, selected, orcontrolled using a combination of bit lines (BLs) and select gates,etc., and specific memory cells at one or more tiers in the specificstrings can be accessed, selected, or controlled using one or moreaccess lines (e.g., word lines).

FIG. 3 illustrates an example schematic diagram of a portion of a NANDarchitecture semiconductor memory array 300 including a plurality ofmemory cells 302 arranged in a two-dimensional array of strings (e.g.,first-third strings 305-307) and tiers (e.g., illustrated as respectiveword lines (WL) WL0-WL7 310-317, a drain-side select gate (SGD) line325, a source-side select gate (SGS) line 330, etc.), and senseamplifiers or devices 360. For example, the memory array 300 canillustrate an example schematic diagram of a portion of one physicalpage of memory cells of a 3D NAND architecture semiconductor memorydevice, such as illustrated in FIG. 2.

Each string of memory cells is coupled to a source line (SRC) using arespective source-side select gate (SGS) (e.g., first-third SGS331-333), and to a respective data line (e.g., first-third bit lines(BL) BL0-BL2 320-322) using a respective drain-side select gate (SGD)(e.g., first-third SGD 326-328). Although illustrated with 8 tiers(e.g., using word lines (WL) WL0-WL7 310-317) and three data lines(BL0-BL2 326-328) in the example of FIG. 3, other examples can includestrings of memory cells having more or fewer tiers or data lines, asdesired.

In a NAND architecture semiconductor memory array, such as the examplememory array 300, the state of a selected memory cell 302 can beaccessed by sensing a current or voltage variation associated with aparticular data line containing the selected memory cell. The memoryarray 300 can be accessed (e.g., by a control circuit, one or moreprocessors, digital logic, etc.) using one or more drivers. In anexample, one or more drivers can activate a specific memory cell, or setof memory cells, by driving a particular potential to one or more datalines (e.g., bit lines BL0-BL2), access lines (e.g., word linesWL0-WL7), or select gates, depending on the type of operation desired tobe performed on the specific memory cell or set of memory cells.

To program or write data to a memory cell, a programming voltage (Vpgm)(e.g., one or more programming pulses, etc.) can be applied to selectedword lines (e.g., WL4), and thus, to a control gate of each memory cellcoupled to the selected word lines (e.g., first-third control gates(CGs) 341-343 of the memory cells coupled to WL4). Programming pulsescan begin, for example, at or near 15V, and, in certain examples, canincrease in magnitude during each programming pulse application. Whilethe program voltage is applied to the selected word lines, a potential,such as a ground potential (e.g., Vss), can be applied to the data lines(e.g., bit lines) and substrates (and thus the channels, between thesources and drains) of the memory cells targeted for programming,resulting in a charge transfer (e.g., direct injection orFowler-Nordheim (FN) tunneling, etc.) from the channels to the floatinggates of the targeted memory cells.

In contrast, a pass voltage (Vpass) can be applied to one or more wordlines having memory cells that are not targeted for programming, or aninhibit voltage (e.g., Vcc) can be applied to data lines (e.g., bitlines) having memory cells that are not targeted for programming, forexample, to inhibit charge from being transferred from the channels tothe floating gates of such non-targeted memory cells. The pass voltagecan be variable, depending, for example, on the proximity of the appliedpass voltages to a word line targeted for programming. The inhibitvoltage can include a supply voltage (Vcc), such as a voltage from anexternal source or supply (e.g., a battery, an AC-to-DC converter,etc.), relative to a ground potential (e.g., Vss).

As an example, if a programming voltage (e.g., 15V or more) is appliedto a specific word line, such as WL4, a pass voltage of 10V can beapplied to one or more other word lines, such as WL3, WL5, etc., toinhibit programming of non-targeted memory cells, or to retain thevalues stored on such memory cells not targeted for programming. As thedistance between an applied program voltage and the non-targeted memorycells increases, the pass voltage required to refrain from programmingthe non-targeted memory cells can decrease. For example, where aprogramming voltage of 15V is applied to WL4, a pass voltage of 10V canbe applied to WL3 and WL5, a pass voltage of 8V can be applied to WL2and WL6, a pass voltage of 7V can be applied to WL1 and WL7, etc. Inother examples, the pass voltages, or number of word lines, etc., can behigher or lower, or more or less.

The sense amplifiers 360, coupled to one or more of the data lines(e.g., first, second, or third bit lines (BL0-BL2) 320-322), can detectthe state of each memory cell in respective data lines by sensing avoltage or current on a particular data line.

Between applications of one or more programming pulses (e.g., Vpgm), averify operation can be performed to determine if a selected memory cellhas reached its intended programmed state. If the selected memory cellhas reached its intended programmed state, it can be inhibited fromfurther programming. If the selected memory cell has not reached itsintended programmed state, additional programming pulses can be applied.If the selected memory cell has not reached its intended programmedstate after a particular number of programming pulses (e.g., a maximumnumber), the selected memory cell, or a string, block, or pageassociated with such selected memory cell, can be marked as defective.

To erase a memory cell or a group of memory cells (e.g., erasure istypically performed in blocks or sub-blocks), an erasure voltage (Vers)(e.g., typically Vpgm) can be applied to the substrates (and thus thechannels, between the sources and drains) of the memory cells targetedfor erasure (e.g., using one or more bit lines, select gates, etc.),while the word lines of the targeted memory cells are kept at apotential, such as a ground potential (e.g., Vss), resulting in a chargetransfer (e.g., direct injection or Fowler-Nordheim (FN) tunneling,etc.) from the floating gates of the targeted memory cells to thechannels.

FIG. 4 illustrates an example block diagram of a memory device 400including a memory array 402 having a plurality of memory cells 404, andone or more circuits or components to provide communication with, orperform one or more memory operations on, the memory array 402. Thememory device 400 can include a row decoder 412, a column decoder 414,sense amplifiers 420, a page buffer 422, a selector 424, an input/output(I/O) circuit 426, and a memory control unit 430.

The memory cells 404 of the memory array 402 can be arranged in blocks,such as first and second blocks 402A, 402B. Each block can includesub-blocks. For example, the first block 402A can include first andsecond sub-blocks 402A₀, 402A_(n), and the second block 402B can includefirst and second sub-blocks 402B₀, 402B_(n). Each sub-block can includea number of physical pages, each page including a number of memory cells404. Although illustrated herein as having two blocks, each block havingtwo sub-blocks, and each sub-block having a number of memory cells 404,in other examples, the memory array 402 can include more or fewerblocks, sub-blocks, memory cells, etc. In other examples, the memorycells 404 can be arranged in a number of rows, columns, pages,sub-blocks, blocks, etc., and accessed using, for example, access lines406, first data lines 410, or one or more select gates, source lines,etc.

The memory control unit 430 can control memory operations of the memorydevice 400 according to one or more signals or instructions received oncontrol lines 432, including, for example, one or more clock signals orcontrol signals that indicate a desired operation (e.g., write, read,erase, etc.), or address signals (A0-AX) received on one or more addresslines 416. One or more devices external to the memory device 400 cancontrol the values of the control signals on the control lines 432, orthe address signals on the address line 416. Examples of devicesexternal to the memory device 400 can include, but are not limited to, ahost, a memory controller, a processor, or one or more circuits orcomponents not illustrated in FIG. 4.

The memory device 400 can use access lines 406 and first data lines 410to transfer data to (e.g., write or erase) or from (e.g., read) one ormore of the memory cells 404. The row decoder 412 and the column decoder414 can receive and decode the address signals (A0-AX) from the addressline 416, can determine which of the memory cells 404 are to beaccessed, and can provide signals to one or more of the access lines 406(e.g., one or more of a plurality of word lines (WL0-WLm)) or the firstdata lines 410 (e.g., one or more of a plurality of bit lines(BL0-BLn)), such as described above.

The memory device 400 can include sense circuitry, such as the senseamplifiers 420, configured to determine the values of data on (e.g.,read), or to determine the values of data to be written to, the memorycells 404 using the first data lines 410. For example, in a selectedstring of memory cells 404, one or more of the sense amplifiers 420 canread a logic level in the selected memory cell 404 in response to a readcurrent flowing in the memory array 402 through the selected string tothe data lines 410.

One or more devices external to the memory device 400 can communicatewith the memory device 400 using the I/O lines (DQ0-DQN) 408, addresslines 416 (A0-AX), or control lines 432. The input/output (I/O) circuit426 can transfer values of data in or out of the memory device 400, suchas in or out of the page buffer 422 or the memory array 402, using theI/O lines 408, according to, for example, the control lines 432 andaddress lines 416. The page buffer 422 can store data received from theone or more devices external to the memory device 400 before the data isprogrammed into relevant portions of the memory array 402, or can storedata read from the memory array 402 before the data is transmitted tothe one or more devices external to the memory device 400.

The column decoder 414 can receive and decode address signals (A0-AX)into one or more column select signals (CSEL1-CSELn). The selector 424(e.g., a select circuit) can receive the column select signals(CSEL1-CSELn) and select data in the page buffer 422 representing valuesof data to be read from or to be programmed into memory cells 404.Selected data can be transferred between the page buffer 422 and the I/Ocircuit 426 using second data lines 418.

The memory control unit 430 can receive positive and negative supplysignals, such as a supply voltage (Vcc) 434 and a negative supply (Vss)436 (e.g., a ground potential), from an external source or supply (e.g.,an internal or external battery, an AC-to-DC converter, etc.). Incertain examples, the memory control unit 430 can include a regulator428 to internally provide positive or negative supply signals.

ECC and other techniques have increased the reliability of NAND devicessubstantially. Nonetheless, there are certain circumstances in whichadditional protection against data loss is desired. For example, asshown in FIG. 5, a write operation that has a programming failure whileprogramming page line X, 510, may corrupt many pages inside that plane.As shown in FIG. 5, all pages in the plane (e.g., plane 1) have beencorrupted by the programming failure of page line X, 510. Similarly, andas shown in FIG. 6, an asynchronous power loss (loss of power to theNAND device without warning) during programming of a first page line X,607 may also corrupt a different page line Z, 605.

As used herein, a page line is a logical construct that identifies agroup of pages comprising pages at a same position in each plane in agroup of planes. Thus, for example, the first page in planes 0-3 isidentified by page line 0. A page is made up of memory cells belongingto the same word line. A block is a group of pages—i.e., all NANDstrings that share the same group of word lines (a NAND string is agroup of NAND cells connected in series). In some NAND configurations, ablock is a smallest erasable unit. A page is a smallest addressable unitfor reading and writing. A plane is a group of physical blocks on asingle NAND die, configured for operation such that physical blocks fromeach of multiple planes can be erased in parallel (i.e., during a giventime interval the physical blocks can be erased essentiallysimultaneously, or in overlap with one another), but only a singlephysical block in any individual plane can be erased at any one time.There may be multiple planes per NAND die. As shown in FIGS. 5-8, 10,and 12-14 a plane is represented by a single physical block (chosen fromthe list of physical blocks of that plane)—so for example, in FIG. 5,the plane depicts the list of pages in that selected physical block, butthere are additional physical blocks not shown for purposes of clarity.

Disclosed in some examples are improvements to NAND devices that provideadditional data protection through an improved NAND data placementschema that allows for recovery from the failure scenarios described inFIG. 5 and FIG. 6. The present disclosure stripes data portions acrosspage lines and planes to ensure that a power failure or programmingerror affecting an entire page line or plane does not corrupt the entiredata item and at most corrupts a single portion of the data item. Insome examples, parity information may be calculated and stored until theprogramming is finished. This parity information may be utilized torecover from corruption of a portion of the data item.

For example, the NAND may receive a data item from a host device. Thisdata item may be split into a number of portions. For purposes of thepresent description, example will be utilized in which a receive dataitem is split into four portions. As will be readily apparent to personsskilled in the art having the benefit of this disclosure, receive dataitems may be split into fewer or a greater number of portions. A firstportion may be programmed at a first location in the NAND, a secondportion at a second location, a third portion at a third location, and afourth portion at a fourth location. The first location, secondlocation, third location, and fourth location may be selected such thatthe first portion, second portion, third portion, and fourth portion arestored in memory cells that are on different page lines and differentplanes with respect to each other. Different locations for the first,second, third, and fourth portions may include different planes, pages,dies, blocks, and the like. In some examples, the first, second, third,and fourth portions may be stored on a same die. The first, second,third, and fourth portions may be coupled in various relations to one ormore other portions. For example, in some examples, the first and secondportions may be stored adjacent to each other in terms of being storedin adjacent page lines and adjacent planes (e.g., as shown in FIG. 7).As used herein, adjacent means a next page line and/or plane insequence. In some examples, the second and third portions may be storedadjacent to each other in terms of being stored in adjacent page linesand adjacent planes. In some examples, the third and fourth portions maybe stored adjacent to each other in terms of being stored in adjacentpage lines and adjacent planes. See for example, FIGS. 1, 710, 715, 720,and 725 (discussed in more detail below). The portions of data are thusstored so that corruption on a single plane or a single word line doesnot corrupt more than a single portion of the data. This enables theNAND to reconstruct the corrupted portion using the parity data. In someexamples, each of the first, second, and third portions may be,respectively, a lower page, an extra page, and an upper page relative toone another. In these examples, the fourth portion may be a copy of oneof the first, second, and third portions.

FIGS. 7 and 8 show an improved NAND data placement schema of data on aTLC NAND array 700 with four planes and 216 page lines according to someexamples of the present disclosure (page lines 24-203 not shown forclarity). FIG. 8 is an extension of the chart of FIG. 7 showing pagelines 204-215. In some examples TLC NAND array 700 may be on a singledie with four planes. As shown in FIG. 7, page lines of a NAND arerepresented by rows and planes of the NAND are represented by columns.Data items (denoted P_(n)) that are to be programmed are divided intoportions, a first P_(n), a second P_(n), a third P_(n), and a fourthP_(n) where n denotes different data items. For example, a first dataitem received by a host may be partitioned into portions: first P₁,second P₁, third P₁, and fourth P₁. A data item may be a page, a word, ablock, or any other unit of data sent by a host.

Example portions may include a lower page, an upper page, and an extrapage that correspond to the TLC programming pages for the data item. Insome examples, for pages 0-3, the first P_(n) may be a lower page, thesecond P_(n) may be an extra page, and the third P, may be an upper pagecorresponding to the programming sequences of a TLC memory. In the caseof TLC NAND, the fourth P_(n) may be a copy of the first P_(n)—that isthe fourth P_(n) may be written with the same data as what was writtenin the first P_(n). For QLC NAND the fourth P_(n) may be the fourthprogramming page. As shown in FIG. 7, in one example improved NAND dataplacement schema, the portions are striped diagonally such that eachportion of a particular data item P_(x) is on a different plane and adifferent page from the other portions. In some examples, each portionof a data item P_(x) may be placed in a page line and on a plane onegreater than the previous portion. Thus, the first portion may be placedat a position of (Page Line X, Plane Y), the second portion may beplaced at a position of (Page Line X+1, Plane Y+1), the third portionmay be placed at a position of (Page Line X+2, Plane Y+2), and thefourth portion may be placed at a position of (Page Line X+3, PlaneY+3). It will be appreciated that “first,” “second,” “third,” and“fourth” portions are merely convenient descriptors for differentportions of the data.

When placing the portions, the plane may wrap around to the first plane.For example, as shown in FIG. 7, a first portion of P₃ is placed inplane 2 (page 0), the second portion may be placed in plane 3 (page 1),and the third portion may wraparound and be placed in plane 0 (page 2),and the fourth portion may be placed in plane 1 (page 3). This dataplacement scheme ensures that that error conditions shown in FIG. 5 andFIG. 6 can only affect at most a single portion of a data item P_(n). Asshown, a portion may be repeated, such as a first portion (e.g., at725).

In some examples, data is written to the NAND in groups of four dataitems P₁-P₄ across four page lines (page lines 0-3) and four plane lines(planes 0-3). As can be appreciated, each page line (represented as arow in FIGS. 7 and 8) may store a same portion of different data items(e.g., first portions of data items P₁, P₂, P₃, P₄ is written in page 0in plane 0, plane 1, plane 2, and plane 3 respectively). As can beappreciated, each plane may store a different portion of different dataitems—that is, each plane stores a first portion, a second portion, athird portion, and a fourth portion, but each portion belongs to adifferent P_(x). For each successive next page line, a different portionof the data items are written and the data item is shifted to the rightby one (with a wraparound) to prevent a second portion of a same dataitem from being written to a same plane—thus page line 1 may store thesecond portions of data items P₁, P₂, P₃, and P₄, but written to a planethat is one over from the page above—thus, plane 1, plane 2, plane 3,and plane 0 respectively.

In some examples, the first portion for a first group of four data items(e.g., First P₁, First P₂, First P₃, First P₄) may correspond to a lowerpage of an SLC NAND, the second portion (Second P₁, Second P₂, SecondP₃, Second P₄) may correspond to an extra page, the third portion (ThirdP₁, Third P₂, Third P₃, Third P₄) may correspond to an upper page, andthe fourth portion (Fourth P₁, Fourth P₂, Fourth P₃, Fourth P₄) maycorrespond (in a TLC NAND) to a copy of the first portion (the lowerpage).

In some examples, the mapping between pages and portions as shown in thefigure may be the same for all groups of data items. A group isrepresented in FIG. 7 by the dotted box and in FIG. 7 comprises a groupof four data items. For example, for group 2 (page lines 4-7), the firstportion may be the lower page, the second portion may be the upper page,the third portion may be an extra page, and the fourth portion may be acopy of the lower page. As can be appreciated, larger or smaller groupsizes may be utilized. Thus a group may comprise 8 data items P₁-P₈ andmay span eight planes and eight pages.

In other examples, instead of the first portion storing a lower page,the second portion storing the extra page, the third portion storing theupper page, and the fourth portion storing a copy of the first portionfor all groups—the portion stored may shift for each group. For example,for group 2 (page lines 4-7), the mappings between the portions and thepages may change such that the first portion may store the extra page,the second portion may store an upper page, the third portion may storea lower page, and the fourth portion may be a copy of the first portion(the extra page). For group 3 (pages 8-11), the mapping between theportions and the pages may shift again—thus the first portion may be anupper page, the second portion may be a lower page, the third portionmay be an extra page, and the fourth portion may be the same as thefirst portion (the upper page). For group 4 (pages 12-15), theprogramming page assigned to the various portions may shift again to bethe same as that in pages 0-3, and so on. Thus, the cycle is:

Page line Plane (0 . . . 3) 0 Lower 1 Extra 2 Upper 3 Lower 4 Extra 5Upper 6 Lower 7 Extra 8 Upper 9 Lower 10 Extra 11 Upper . . . . . .

In addition to the diagonal portion placement scheme, a parity page maybe calculated from the data item portions. For example, the parity pagemay be an XOR of the data in the first portion, second portion, thirdportions, and fourth portions. For example:

Parity_(n)=First Portion P _(n)⊕Second Portion P _(n)⊕Third Portion P_(n)⊕Fourth Portion P _(n)

where ⊕ is an XOR operator.

The parity values may be calculated and temporarily stored in volatilememory (e.g., RAM) and then stored periodically in non-volatile storagein a separate NAND block from the user data. The diagonal placement ofthe portions of the page data ensures that if a defect in programming oran asynchronous power loss wipes out a whole page, or a whole plane,that the rest of the data is recoverable as at most, only one portion ofthe data item will be lost, and due to the XOR parity data, it is thusrecoverable.

FIG. 9 illustrates a logical placement of the parity pages in a volatilememory of the controller or other component of the NAND according tosome examples of the present disclosure. The parity pages shown in FIG.9 are parity pages that are calculated for the P_(n) data items in FIGS.7 and 8. As the data items are programmed to the NAND in FIG. 7, theparity can be calculated and stored in volatile memory (e.g., RandomAccess Memory). At a first time, T0, the portions of data items P₁-P₁₂can be written to page lines 0-11 and plane 0-3 of die 700. At the sametime, the parity values of these data items: 902-924 can be calculatedand stored in volatile storage such as RAM, as shown in FIG. 9.

At time T1, the portions of data items P₁₃-P₂₄ are written to page lines12-23 and the corresponding parities are calculated in stored in RAM, asshown in FIG. 9. In some examples, the parity values 902-924 areoverwritten with the parity values 926-948. In some examples, the parityvalues 902-924 may be written to NAND before they are overwritten, forexample, to a reliable SLC block. Similarly, at time T2 parity valuesfor pages 25-36 can be calculated and stored as those pages are written.

FIG. 10 shows a schematic of a parity page storage 1000 used to storethe parity pages in nonvolatile NAND. In the example of FIG. 10, theparity page storage 1000 may be configured as SLC blocks for increasedreliability. The parity page storage 1000 as shown in FIG. 10 may be ina separate location from the location that stores the user data (e.g.,TLC NAND array 700 from FIG. 7) from which the parity pages aregenerated. In other examples, the parity pages may be stored on a samedie as the user data from which the parity pages are generated. Paritypages 1-12 are stored at time T0. Flushed page line count (FPC)indicates the number of page lines of programmed user data (e.g., on die700). Parity pages 13-24 are stored at time T1, and so on until paritypages 205-216 are stored at time T17.

The parity data stored in RAM or in the SLC 1000 may be used to recovera page of user data. Turning back to FIG. 7, if plane 1 is corrupted (asshown in FIG. 5), only a single portion of the P_(n) data items may becorrupted by virtue of the failure on plane 1. The system may utilizethe parity data to recover these portions. A_(n) individual portion ofthe user data may be recoverable by applying an XOR operation on theremaining pages and the parity page. For example, if Plane 1 iscorrupted, the second portion of the P₁ data item 715 may be corrupted.This portion may be recovered by XORing the first portion of P₁ 710,third portion P₁ 720, fourth portion P₁, and the parity P1 902.Similarly, if a page line is corrupted as shown in FIG. 6, only a singleportion of the user data page may be lost. For example, if any one ofpage lines 0-3 of FIG. 7 are corrupted, only a single portion of aparticular user page may be lost. For example, if the pages on page line1 are corrupted, then the second portion of P₁ 715 is corrupted, but thefirst, second, and fourth portions are not and as a result, the thirdportion may be reconstructed using the parity value. For example, by:

Second Portion P ₁=First Portion P ₁⊕Third Portion P ₁ ⊕Fourth Portion P₁⊕Parity P ₁

Thus, both horizontal corruption across planes on a same page line andvertical corruption affecting all page lines of a plane can berecoverable as a result of the positional rotation of the portions ofthe user data.

FIG. 11 shows a flowchart of a method 1100 of applying an improved NANDdata placement schema to storing data on a NAND die of a NAND deviceaccording to some examples of the present disclosure. A host device maysend a data item to write to the NAND. This data item may be programmedto the NAND in a number of portions—a first portion, second portion,third portion, and fourth portion. Example portions may correspond to anupper page, lower page, and extra page of a TLC NAND. In other examples,the data item may be portioned into only two portions (corresponding toa lower page and upper page of an MLC NAND), or four portions(corresponding to a lower page, upper page, middle page, and extra pagefor a QLC NAND). In other examples, the portions may not correspond tothe programming phases of the NAND, but may be divided in other ways(e.g., the most significant bits, least significant bits, and the like).In some examples, the programming page of the NAND that corresponds tothe portion may shift based upon a grouping of data items. Thus, in afirst grouping of data items, the lower page is written on the firstpage line of the group and on a later grouping of data items, the extrapage may be written on the first page line of the group and so on.

At operation 1102 the controller may program a first portion of thereceived data into the NAND array at a first page line and a firstplane. At operation 1104 the controller may program a second portion ofthe received data into the NAND array at a second page line and a secondplane. At operation 1106 the controller may program a third portion ofthe received data into the NAND array at a third page line and a thirdplane. At operation 1107 the controller may program a fourth portion ofthe received data into the NAND array at a fourth page line and a fourthplane. In some examples, the fourth portion is a copy of one of thefirst, second, third, or fourth portions. For example, the fourthportion may be a copy of the portion written first (e.g., a firstportion) for the group. The first page line, second page line, thirdpage line, fourth page line, first plane, second plane, third plane, andfourth plane may be selected such that the first portion, secondportion, third portion, and fourth portions of a particular data itemare programmed into memory cells that are on different page lines andare on different planes with respect to each other. In some examples,all the locations are on the same die. At operation 1108, the NANDmemory device may calculate a parity value for the data item using thefirst, second, and third portions. This parity value may be stored involatile, or non-volatile memory.

While the above data placement schema minimizes data loss by strategicplacement of data and the use of parity values, the parity values may bediscarded upon completion of the NAND block programming for the data towhich the parity corresponds. While this saves the overhead of storingthe parity data, this parity data may be leveraged along with the samedata placement schema to recover from an Uncorrectable Error CorrectionCode (UECC) situation in which the NAND cannot recover the data withtraditional ECC. For example, as shown in FIG. 12, plane 1, page lines Zto Z+5 may suffer from an unrecoverable ECC error.

By storing the data in the improved NAND data placement schema above,losing a single portion of the data is recoverable with the parityvalue. This may be costly in terms of additional overhead for storingthe parity values. Disclosed in some examples, are methods, systems,memory devices, and machine-readable mediums for clustered paritystorage for NAND devices utilizing the above disclosed improved dataplacement schemas. Rather than storing each parity value, parity valuesfrom multiple data items may be combined using an XOR operation andstored in a compressed form to reduce the overprovisioning utilized tosave the parity values. A compressed parity value may be a consolidationof multiple parity values, for example, an XOR combination of two ormore parity values.

For example, FIG. 13 shows an SLC NAND block 1300 storing a plurality ofparity values that are arranged in a plurality of clusters. In FIG. 13,they are arranged in 16 clusters of 54 page lines of four planes foreach cluster. Each cluster thus contains 216 parity values. Each parityvalue corresponds to a data item (e.g., from FIG. 10). A firstcompressed parity value may be created by XORing parity values in a sameposition from each different cluster. For example, a compressed parityvalue may be created from an XOR of the parity value 1, parity value217, and so on until parity value 3241. This is represented by the darkline in FIG. 13. A second compressed parity value may be created byXORing the second parity value in each cluster. For example, parity 2,parity 218, and so on until parity value 3242. Clusters 2-14 are notshown for compactness and clarity but are included in the XORcalculations.

More generally, a set of compressed parity values may be created. Eachparity value in each cluster may be referred to by using a relativeposition in the cluster using a notation: (cluster, page, plane). Forexample, parity value 1 in FIG. 13 may be (0, 0, 0) which indicates thisparity value is in cluster 0, page 0, and plane 0. The page values maybe relative to the cluster i.e., parity 3241 may be addressed by (15, 0,0) as it is in the first page and the first plane of cluster 15 eventhough it is in page line 810 overall. The compressed parity values maybe calculated by XORing the parity values of same relative positions ofall clusters. For example:

Compressed Parity(X,Y)=(0,X,Y)⊕(1,X,Y)⊕(2,X,Y)⊕(3,X,Y)⊕(4,X,Y)⊕(5,X,Y)⊕(6,X,Y)⊕(7,X,Y)⊕(8,X,Y)⊕(9,X,Y)⊕(10,X,Y)⊕(11,X,Y)⊕(12,X,Y)⊕(13,X,Y)⊕(14,X,Y)⊕(15,X,Y)

As shown in FIG. 13, values of X is of a range 0-53 and Y is a range of0-3.

As shown in FIG. 14, these compressed parity values may be stored in theNAND and may be denoted PARITYX_(a). In some examples, the compressedparity and/or the uncompressed parity values may be stored in theoriginal NAND block before the original block is closed. Theuncompressed values may then be deleted and the space freed up for othervalues (e.g., the compressed parity values). The group of data itemsP_(n) that were used to calculate the parity values that were used tocalculate a compressed parity value may be called a compressed paritydata item group G_(n). For example, if FIG. 13 shows parity values thatcorrespond to data items P_(n) from FIG. 7, all portions of data itemsthat were used to produce the constituent parity values (e.g., parity 1,parity 217, and so on until parity 3241) for a first compressed parityvalue may be part of compressed parity data item group G₁. For parityvalue 1, the portions of the data items may include first P₁, second P₁,third P₁, and fourth P₁ from FIG. 7.

Should an uncorrectable ECC error happen, such as shown in FIG. 12, theNAND device may utilize the compressed parity value to recreate theportion of the data item lost. By XORing the compressed parity value andthe values of the data item portions in the group G_(n) (excluding ofcourse the corrupted portion), the corrupted portion of the data itemmay be recovered. For example, in the case of a first portion of dataitem P₁ from (FIG. 7) being unrecoverable, the system may XOR thecompressed parity value PARITYX1, and the data portions in the group G₁(including the second, third, and fourth portions of data item P₁) withthe exception of the first portion of data item P₁ to recover the dataitem P₁.

FIG. 15 illustrates a flow chart of a method of clustering parity valuesaccording to some examples of the present disclosure. At operation 1502,incoming data may be stored according to the disclosed improved NANDdata placement schema. For example, storing a received data item inmemory cells of the NAND array such that a first portion, secondportion, third portion, and fourth portion of the data item are storedin memory cells in the array that are on different page lines anddifferent planes with respect to each other as illustrated in FIG. 7. Atoperation 1504, a parity value may be calculated for a received dataitem and stored in volatile or non-volatile storage. As noted, theparity value may be the XOR of the portions of the data item. Atoperation 1506, the NAND device may assign the parity value calculatedat operation 1504 into a position of a parity cluster. For example, afirst position of the parity cluster. At operation 1508, using a sameposition of each of the clusters, a compressed parity value may becalculated. For example, by applying an XOR operator to the parity valuein a same position in each cluster of parity values.

This compressed parity value may be utilized to recover a data portionas previously described. For example, by XORing the data portions in thecompressed parity data item group (with the exception of the dataportion that was corrupted) and the compressed parity, the data portionthat was corrupted may be recovered.

For example if we have the following data items P_(n) belonging to thefirst parity value (e.g., first page line and the first plane) in eachparity value cluster:

First Second Third Fourth P_(n) portion portion portion PortionParity_(n) 1 010 111 000 010 111 54 101 001 110 101 111 810 000 110 010000 100

Then the compressed parity for the group of P_(n) data items in thetable (G₁) is the XOR of 111, 111, and 100 which is 100. To recover alost portion of data, say the second portion of P₅₄ the systemcalculates the XOR of 010, 111, 000, 010, 101, 110, 101, 000, 110, 010,000 and 100 (which is the compressed parity). This results in: 001 whichis the correct value. Note that the example table and example above issimplified by having only three P values (1, 54, and 810) and leavingout values for P₁₀₈ that would be in group G₁ as shown in FIG. 13.

FIG. 16 illustrates a schematic of a memory controller 1615 according tosome examples of the present disclosure. Memory controller 1615 is anexample of memory controller 115, memory manager 1625 is an example ofmemory manager 125, management tables 1630 may be an example ofmanagement table 130. Controller 1635 and ECC 1640 may be an example ofcontroller 135 and ECC 140 of FIG. 1. Controller 1635 includes a schemacontroller 1642 that may determine where to store portions of dataitems. In some examples, the positioning is in accordance with the NANDdata placement schema disclosed herein. For example, placing a firstportion of a received data item into the array at a first page line of aplurality of page lines of a NAND and at a first plane of a plurality ofplanes; programming a second portion of the received data item into thearray at a second page line of the plurality of page lines and at asecond plane of the plurality of planes; programming a third portion ofthe received data item into the array at a third page line of theplurality of page lines and at a third plane of the plurality of planes;calculating a parity value for the data item using the first portion,second portion, and third portion; and wherein the first page line,second page line, third page line, first plane, second plane, and thirdplane are selected such that the first portion, second portion and thirdportion are stored in memory cells that are on different page lines anddifferent planes with respect to each other. For example, schemacontroller 1642 may position data in the NAND as shown in FIGS. 7 and 8.

In some examples, the schema controller 1642 may also calculate one ormore parity values. In some examples, the parity values may becalculated by a hardware XOR processor.

The schema controller 1642 may allocate and assign parity values tovolatile memory locations (as shown in FIG. 9), non-volatile memorylocations (as shown in FIG. 10) and the like. Schema controller 1642 mayassign the parity values to clusters and utilize a parity value fromeach cluster to create a compressed parity value and that compressedparity value may be stored. The parity value utilized from each clustermay be selected based upon a formula or other schema. For example, eachparity value may be assigned a relative position in each cluster (e.g.,a first parity value in a cluster, a second parity value, and so on) anda same position in each cluster may be utilized to create the compressedparity value. The schema controller 1642 may store the compressed parityvalues in volatile or non-volatile memory (e.g., as shown in FIG. 14).Schema controller 1642 may implement the methods of FIG. 11 and FIG. 15.

FIG. 17 illustrates a block diagram of an example machine 1700 uponwhich any one or more of the techniques (e.g., methodologies) discussedherein may perform. In alternative embodiments, the machine 1700 mayoperate as a standalone device or may be connected (e.g., networked) toother machines. In a networked deployment, the machine 1700 may operatein the capacity of a server machine, a client machine, or both inserver-client network environments. In an example, the machine 1700 mayact as a peer machine in peer-to-peer (P2P) (or other distributed)network environment. The machine 1700 may be a personal computer (PC), atablet PC, a set-top box (STB), a personal digital assistant (PDA), amobile telephone, a web appliance, an IoT device, automotive system, orany machine capable of executing instructions (sequential or otherwise)that specify actions to be taken by that machine. Further, while only asingle machine is illustrated, the term “machine” shall also be taken toinclude any collection of machines that individually or jointly executea set (or multiple sets) of instructions to perform any one or more ofthe methodologies discussed herein, such as cloud computing, software asa service (SaaS), other computer cluster configurations.

Examples, as described herein, may include, or may operate by, logic,components, devices, packages, or mechanisms. Circuitry is a collection(e.g., set) of circuits implemented in tangible entities that includehardware (e.g., simple circuits, gates, logic, etc.). Circuitrymembership may be flexible over time and underlying hardwarevariability. Circuitries include members that may, alone or incombination, perform specific tasks when operating. In an example,hardware of the circuitry may be immutably designed to carry out aspecific operation (e.g., hardwired). In an example, the hardware of thecircuitry may include variably connected physical components (e.g.,execution units, transistors, simple circuits, etc.) including acomputer readable medium physically modified (e.g., magnetically,electrically, moveable placement of invariant massed particles, etc.) toencode instructions of the specific operation. In connecting thephysical components, the underlying electrical properties of a hardwareconstituent are changed, for example, from an insulator to a conductoror vice versa. The instructions enable participating hardware (e.g., theexecution units or a loading mechanism) to create members of thecircuitry in hardware via the variable connections to carry out portionsof the specific tasks when in operation. Accordingly, the computerreadable medium is communicatively coupled to the other components ofthe circuitry when the device is operating. In an example, any of thephysical components may be used in more than one member of more than onecircuitry. For example, under operation, execution units may be used ina first circuit of a first circuitry at one point in time and reused bya second circuit in the first circuitry, or by a third circuit in asecond circuitry at a different time.

The machine (e.g., computer system) 1700 (e.g., the host device 105, thememory device 110, etc.) may include a hardware processor 1702 (e.g., acentral processing unit (CPU), a graphics processing unit (GPU), ahardware processor core, or any combination thereof, such as the memorycontroller 115, etc.), a main memory 1704 and a static memory 1706, someor all of which may communicate with each other via an interlink (e.g.,bus) 1708. The machine 1700 may further include a display unit 1710, analphanumeric input device 1712 (e.g., a keyboard), and a user interface(UI) navigation device 1714 (e.g., a mouse). In an example, the displayunit 1710, input device 1712 and UI navigation device 1714 may be atouch screen display. The machine 1700 may additionally include astorage device (e.g., drive unit) 1716, a signal generation device 1718(e.g., a speaker), a network interface device 1720, and one or moresensors 1716, such as a global positioning system (GPS) sensor, compass,accelerometer, or other sensor. The machine 1700 may include an outputcontroller 1728, such as a serial (e.g., universal serial bus (USB),parallel, or other wired or wireless (e.g., infrared (IR), near fieldcommunication (NFC), etc.) connection to communicate or control one ormore peripheral devices (e.g., a printer, card reader, etc.).

The storage device 1716 may include a machine readable medium 1722 onwhich is stored one or more sets of data structures or instructions 1724(e.g., software) embodying or utilized by any one or more of thetechniques or functions described herein. The instructions 1724 may alsoreside, completely or at least partially, within the main memory 1704,within static memory 1706, or within the hardware processor 1702 duringexecution thereof by the machine 1700. In an example, one or anycombination of the hardware processor 1702, the main memory 1704, thestatic memory 1706, or the storage device 1716 may constitute themachine readable medium 1722.

While the machine readable medium 1722 is illustrated as a singlemedium, the term “machine readable medium” may include a single mediumor multiple media (e.g., a centralized or distributed database, orassociated caches and servers) configured to store the one or moreinstructions 1724.

The term “machine readable medium” may include any medium capable ofstoring, encoding, or carrying instructions for execution by the machine1700 and that cause the machine 1700 to perform any one or more of thetechniques of the present disclosure, or capable of storing, encoding orcarrying data structures used by or associated with such instructions.Non-limiting machine readable medium examples may include solid-statememories, and optical and magnetic media. In an example, a massedmachine readable medium comprises a machine-readable medium with aplurality of particles having invariant (e.g., rest) mass. Accordingly,massed machine-readable media are not transitory propagating signals.Specific examples of massed machine readable media may include:non-volatile memory, such as semiconductor memory devices (e.g.,Electrically Programmable Read-Only Memory (EPROM), ElectricallyErasable Programmable Read-Only Memory (EEPROM)) and flash memorydevices; magnetic disks, such as internal hard disks and removabledisks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 1724 (e.g., software, programs, an operating system(OS), etc.) or other data are stored on the storage device 1721, can beaccessed by the memory 1704 for use by the processor 1702. The memory1704 (e.g., DRAM) is typically fast, but volatile, and thus a differenttype of storage than the storage device 1721 (e.g., an SSD), which issuitable for long-term storage, including while in an “off” condition.The instructions 1724 or data in use by a user or the machine 1700 aretypically loaded in the memory 1704 for use by the processor 1702. Whenthe memory 1704 is full, virtual space from the storage device 1721 canbe allocated to supplement the memory 1704; however, because the storage1721 device is typically slower than the memory 1704, and write speedsare typically at least twice as slow as read speeds, use of virtualmemory can greatly reduce user experience due to storage device latency(in contrast to the memory 1704, e.g., DRAM). Further, use of thestorage device 1721 for virtual memory can greatly reduce the usablelifespan of the storage device 1721.

In contrast to virtual memory, virtual memory compression (e.g., theLinux® kernel feature “ZRAM”) uses part of the memory as compressedblock storage to avoid paging to the storage device 1721. Paging takesplace in the compressed block until it is necessary to write such datato the storage device 1721. Virtual memory compression increases theusable size of memory 1704, while reducing wear on the storage device1721.

Storage devices optimized for mobile electronic devices, or mobilestorage, traditionally include MMC solid-state storage devices (e.g.,micro Secure Digital (microSD™) cards, etc.). MMC devices include anumber of parallel interfaces (e.g., an 8-bit parallel interface) with ahost device, and are often removable and separate components from thehost device. In contrast, eMMC™ devices are attached to a circuit boardand considered a component of the host device, with read speeds thatrival serial ATA™ (Serial AT (Advanced Technology) Attachment, or SATA)based SSD devices. However, demand for mobile device performancecontinues to increase, such as to fully enable virtual oraugmented-reality devices, utilize increasing networks speeds, etc. Inresponse to this demand, storage devices have shifted from parallel toserial communication interfaces. Universal Flash Storage (UFS) devices,including controllers and firmware, communicate with a host device usinga low-voltage differential signaling (LVDS) serial interface withdedicated read/write paths, further advancing greater read/write speeds.

The instructions 1724 may further be transmitted or received over acommunications network 1726 using a transmission medium via the networkinterface device 1720 utilizing any one of a number of transferprotocols (e.g., frame relay, internet protocol (IP), transmissioncontrol protocol (TCP), user datagram protocol (UDP), hypertext transferprotocol (HTTP), etc.). Example communication networks may include alocal area network (LAN), a wide area network (WAN), a packet datanetwork (e.g., the Internet), mobile telephone networks (e.g., cellularnetworks), Plain Old Telephone (POTS) networks, and wireless datanetworks (e.g., Institute of Electrical and Electronics Engineers (IEEE)802.11 family of standards known as Wi-Fi®, IEEE 802.16 family ofstandards known as WiMax®), IEEE 802.15.4 family of standards,peer-to-peer (P2P) networks, among others. In an example, the networkinterface device 1720 may include one or more physical jacks (e.g.,Ethernet, coaxial, or phone jacks) or one or more antennas to connect tothe communications network 1726. In an example, the network interfacedevice 1720 may include a plurality of antennas to wirelesslycommunicate using at least one of single-input multiple-output (SIMO),multiple-input multiple-output (MIMO), or multiple-input single-output(MISO) techniques. The term “transmission medium” shall be taken toinclude any intangible medium capable of storing, encoding or carryinginstructions for execution by the machine 1700, and includes digital oranalog communications signals or other intangible medium to facilitatecommunication of such software.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples”. Such examples can include elements in addition tothose shown or described. However, the present inventors alsocontemplate examples in which only those elements shown or described areprovided. Moreover, the present inventors also contemplate examplesusing any combination or permutation of those elements shown ordescribed (or one or more aspects thereof), either with respect to aparticular example (or one or more aspects thereof), or with respect toother examples (or one or more aspects thereof) shown or describedherein.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” may include “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein”. Also, in the following claims, theterms “including” and “comprising” are open-ended, i.e., a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

In various examples, the components, controllers, processors, units,engines, or tables described herein can include, among other things,physical circuitry or firmware stored on a physical device. As usedherein, “processor” means any type of computational circuit such as, butnot limited to, a microprocessor, a microcontroller, a graphicsprocessor, a digital signal processor (DSP), or any other type ofprocessor or processing circuit, including a group of processors ormulti-core devices.

The term “horizontal” as used in this document is defined as a planeparallel to the conventional plane or surface of a substrate, such asthat underlying a wafer or die, regardless of the actual orientation ofthe substrate at any point in time. The term “vertical” refers to adirection perpendicular to the horizontal as defined above.Prepositions, such as “on,” “over,” and “under” are defined with respectto the conventional plane or surface being on the top or exposed surfaceof the substrate, regardless of the orientation of the substrate; andwhile “on” is intended to suggest a direct contact of one structurerelative to another structure which it lies “on” (in the absence of anexpress indication to the contrary); the terms “over” and “under” areexpressly intended to identify a relative placement of structures (orlayers, features, etc.), which expressly includes—but is not limitedto—direct contact between the identified structures unless specificallyidentified as such. Similarly, the terms “over” and “under” are notlimited to horizontal orientations, as a structure may be “over” areferenced structure if it is, at some point in time, an outermostportion of the construction under discussion, even if such structureextends vertically relative to the referenced structure, rather than ina horizontal orientation.

The terms “wafer” and “substrate” are used herein to refer generally toany structure on which integrated circuits are formed, and also to suchstructures during various stages of integrated circuit fabrication. Thefollowing detailed description is, therefore, not to be taken in alimiting sense, and the scope of the various embodiments is defined onlyby the appended claims, along with the full scope of equivalents towhich such claims are entitled.

Various embodiments according to the present disclosure and describedherein include memory utilizing a vertical structure of memory cells(e.g., NAND strings of memory cells). As used herein, directionaladjectives will be taken relative a surface of a substrate upon whichthe memory cells are formed (i.e., a vertical structure will be taken asextending away from the substrate surface, a bottom end of the verticalstructure will be taken as the end nearest the substrate surface and atop end of the vertical structure will be taken as the end farthest fromthe substrate surface).

As used herein, directional adjectives, such as horizontal, vertical,normal, parallel, perpendicular, etc., can refer to relativeorientations, and are not intended to require strict adherence tospecific geometric properties, unless otherwise noted. For example, asused herein, a vertical structure need not be strictly perpendicular toa surface of a substrate, but may instead be generally perpendicular tothe surface of the substrate, and may form an acute angle with thesurface of the substrate (e.g., between 60 and 120 degrees, etc.).

In some embodiments described herein, different doping configurationsmay be applied to a source-side select gate (SGS), a control gate (CG),and a drain-side select gate (SGD), each of which, in this example, maybe formed of or at least include polysilicon, with the result such thatthese tiers (e.g., polysilicon, etc.) may have different etch rates whenexposed to an etching solution. For example, in a process of forming amonolithic pillar in a 3D semiconductor device, the SGS and the CG mayform recesses, while the SGD may remain less recessed or even notrecessed. These doping configurations may thus enable selective etchinginto the distinct tiers (e.g., SGS, CG, and SGD) in the 3D semiconductordevice by using an etching solution (e.g., tetramethylammonium hydroxide(TMCH)).

Operating a memory cell, as used herein, includes reading from, writingto, or erasing the memory cell. The operation of placing a memory cellin an intended state is referred to herein as “programming,” and caninclude both writing to or erasing from the memory cell (e.g., thememory cell may be programmed to an erased state).

According to one or more embodiments of the present disclosure, a memorycontroller (e.g., a processor, controller, firmware, etc.) locatedinternal or external to a memory device, is capable of determining(e.g., selecting, setting, adjusting, computing, changing, clearing,communicating, adapting, deriving, defining, utilizing, modifying,applying, etc.) a quantity of wear cycles, or a wear state (e.g.,recording wear cycles, counting operations of the memory device as theyoccur, tracking the operations of the memory device it initiates,evaluating the memory device characteristics corresponding to a wearstate, etc.)

According to one or more embodiments of the present disclosure, a memoryaccess device may be configured to provide wear cycle information to thememory device with each memory operation. The memory device controlcircuitry (e.g., control logic) may be programmed to compensate formemory device performance changes corresponding to the wear cycleinformation. The memory device may receive the wear cycle informationand determine one or more operating parameters (e.g., a value,characteristic) in response to the wear cycle information.

It will be understood that when an element is referred to as being “on,”“connected to” or “coupled with” another element, it can be directly on,connected, or coupled with the other element or intervening elements maybe present. In contrast, when an element is referred to as being“directly on,” “directly connected to” or “directly coupled with”another element, there are no intervening elements or layers present. Iftwo elements are shown in the drawings with a line connecting them, thetwo elements can be either be coupled, or directly coupled, unlessotherwise indicated.

Method examples described herein can be machine or computer-implementedat least in part. Some examples can include a computer-readable mediumor machine-readable medium encoded with instructions operable toconfigure an electronic device to perform methods as described in theabove examples. A_(n) implementation of such methods can include code,such as microcode, assembly language code, a higher-level language code,or the like. Such code can include computer readable instructions forperforming various methods. The code may form portions of computerprogram products. Further, the code can be tangibly stored on one ormore volatile or non-volatile tangible computer-readable media, such asduring execution or at other times. Examples of these tangiblecomputer-readable media can include, but are not limited to, hard disks,removable magnetic disks, removable optical disks (e.g., compact discsand digital video disks), magnetic cassettes, memory cards or sticks,random access memories (RAMs), read only memories (ROMs), solid statedrives (SSDs), Universal Flash Storage (UFS) device, embedded MMC (eMMC)device, and the like.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Also, in the above Detailed Description,various features may be grouped together to streamline the disclosure.This should not be interpreted as intending that an unclaimed disclosedfeature is essential to any claim. Rather, inventive subject matter maylie in less than all features of a particular disclosed embodiment.Thus, the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment, and it is contemplated that such embodiments can be combinedwith each other in various combinations or permutations. The scope ofthe invention should be determined with reference to the appendedclaims, along with the full scope of equivalents to which such claimsare entitled.

Other Notes and Examples

Example 1 is a NAND memory device comprising: an array of NAND memorycells organized into multiple planes and addressable by multiple pagelines; and a controller configured to perform operations comprising:programming a first portion of a received data item into the array at afirst page line of the multiple page lines and at a first plane of themultiple planes; programming a second portion of the received data iteminto the array at a second page line of the multiple page lines and at asecond plane of the multiple planes; programming a third portion of thereceived data item into the array at a third page line of the multiplepage lines and at a third plane of the multiple planes.

In Example 2, the subject matter of Example 1, wherein the operationscomprise storing a parity value by applying an XOR operator to the firstportion, second portion, and third portion.

In Example 3, the subject matter of Example 2, wherein the operationsfurther comprise storing the parity value in the array of NAND memorycells.

In Example 4, the subject matter of Example 3, wherein the parity valueis stored in a location of the array of NAND memory cells that areconfigured as Single Level Cell (SLC) memory cells.

In Example 5, the subject matter of any of Examples 3-4, wherein thefirst portion, second portion, and third portion are programmed into alocation of the array of NAND memory cells that are configured as TripleLevel Cell (TLC) memory cells.

In Example 6, the subject matter of any of Examples 2-5, wherein theoperations comprise: determining that one of the first portion, secondportion, or third portion was corrupted; and recovering the one of thefirst portion, second portion, or third portion by utilizing the parityvalue.

In Example 7, the subject matter of any of Examples 2-6 includes, avolatile memory in communication with the controller; and wherein theoperations further comprise: initially storing the parity value in thevolatile memory; and moving the parity value to the array of NAND memorycells.

In Example 8, the subject matter of any of Examples 1-7, wherein theoperations further comprise: programming a fourth portion of thereceived data item into the array at a fourth page line of the multiplepage lines and at a fourth plane of the multiple planes.

In Example 9, the subject matter of any of Examples 1-8, wherein thefirst portion, the second portion and the third portion compriseindividual bits within the received data.

In Example 10, the subject matter of any of Examples 1-9, wherein thethird page line and third plane are greater than the second page lineand second plane, and the second page line and second plane are greaterthan the first page line and first plane.

Example 11 is a method of storing data on a NAND device that includes,an array of NAND memory cells organized into multiple planes andaddressable by multiple page lines, the method comprising: programming afirst portion of a received data item into the array at a first pageline of the multiple page lines and at a first plane of the multipleplanes; programming a second portion of the received data item into thearray at a second page line of the multiple page lines and at a secondplane of the multiple planes; programming a third portion of thereceived data item into the array at a third page line of the multiplepage lines and at a third plane of the multiple planes.

In Example 12, the subject matter of Example 11 includes, storing aparity value by applying an XOR operator to the first portion, secondportion, and third portion.

In Example 13, the subject matter of Example 12 includes, storing theparity value in the array of NAND memory cells.

In Example 14, the subject matter of Example 13, wherein the parityvalue is stored in a location of the array of NAND memory cells that areconfigured as Single Level Cell (SLC) memory cells.

In Example 15, the subject matter of any of Examples 13-14, wherein thefirst portion, second portion, and third portion are programmed into alocation of the array of NAND memory cells that are configured as TripleLevel Cell (TLC) memory cells.

In Example 16, the subject matter of any of Examples 12-15 includes,determining that one of the first portion, second portion, or thirdportion was corrupted; and recovering the one of the first portion,second portion, or third portion by utilizing the parity value.

In Example 17, the subject matter of any of Examples 12-16 includes,initially storing the parity value in a volatile memory; and moving theparity value to the array of NAND memory cells.

In Example 18, the subject matter of any of Examples 11-17 includes,programming a fourth portion of the received data item into the array ata fourth page line of the multiple page lines and at a fourth plane ofthe multiple planes.

In Example 19, the subject matter of any of Examples 11-18, wherein thefirst portion, the second portion and the third portion compriseindividual bits within the received data.

In Example 20, the subject matter of any of Examples 11-19, wherein thethird page line and third plane are greater than the second page lineand second plane, and the second page line and second plane are greaterthan the first page line and first plane.

Example 21 is a machine-readable medium, comprising instructions, whichwhen executed by a machine, cause the machine to perform operationscomprising: programming a first portion of a received data item into aNAND array at a first page line of multiple page lines and at a firstplane of multiple planes of the NAND array; programming a second portionof the received data item into the array at a second page line of themultiple page lines and at a second plane of the multiple planes;programming a third portion of the received data item into the array ata third page line of the multiple page lines and at a third plane of themultiple planes.

In Example 22, the subject matter of Example 21, wherein the operationscomprise storing a parity value by applying an XOR operator to the firstportion, second portion, and third portion.

In Example 23, the subject matter of Example 22, wherein the operationsfurther comprise storing the parity value in the array of NAND memorycells.

In Example 24, the subject matter of Example 23, wherein the parityvalue is stored in a location of the array of NAND memory cells that areconfigured as Single Level Cell (SLC) memory cells.

In Example 25, the subject matter of any of Examples 23-24, wherein thefirst portion, second portion, and third portion are programmed into alocation of the array of NAND memory cells that are configured as TripleLevel Cell (TLC) memory cells.

In Example 26, the subject matter of any of Examples 22-25, wherein theoperations comprise: determining that one of the first portion, secondportion, or third portion was corrupted; and recovering the one of thefirst portion, second portion, or third portion by utilizing the parityvalue.

In Example 27, the subject matter of any of Examples 22-26 includes, avolatile memory in communication with the controller; and wherein theoperations further comprise: initially storing the parity value in thevolatile memory; and moving the parity value to the array of NAND memorycells.

In Example 28, the subject matter of any of Examples 21-27, wherein theoperations further comprise: programming a fourth portion of thereceived data item into the array at a fourth page line of the multiplepage lines and at a fourth plane of the multiple planes.

In Example 29, the subject matter of any of Examples 21-28, wherein thefirst portion, the second portion and the third portion compriseindividual bits within the received data.

In Example 30, the subject matter of any of Examples 21-29, wherein thethird page line and third plane are greater than the second page lineand second plane, and the second page line and second plane are greaterthan the first page line and first plane.

Example 31 is a NAND memory device comprising: an array of NAND memorycells organized into multiple planes and addressable by multiple pagelines; and a controller configured to perform operations comprising:means for programming a first portion of a received data item into thearray at a first page line of the multiple page lines and at a firstplane of the multiple planes; means for programming a second portion ofthe received data item into the array at a second page line of themultiple page lines and at a second plane of the multiple planes; meansfor programming a third portion of the received data item into the arrayat a third page line of the multiple page lines and at a third plane ofthe multiple planes.

In Example 32, the subject matter of Example 31 includes, means forstoring a parity value by applying an XOR operator to the first portion,second portion, and third portion.

In Example 33, the subject matter of Example 32 includes, means forstoring the parity value in the array of NAND memory cells.

In Example 34, the subject matter of Example 33, wherein the parityvalue is stored in a location of the array of NAND memory cells that areconfigured as Single Level Cell (SLC) memory cells.

In Example 35, the subject matter of any of Examples 33-34, wherein thefirst portion, second portion, and third portion are programmed into alocation of the array of NAND memory cells that are configured as TripleLevel Cell (TLC) memory cells.

In Example 36, the subject matter of any of Examples 32-35 includes,means for determining that one of the first portion, second portion, orthird portion was corrupted; and means for recovering the one of thefirst portion, second portion, or third portion by utilizing the parityvalue.

In Example 37, the subject matter of any of Examples 32-36 includes,means for initially storing the parity value in a volatile memory; andmeans for moving the parity value to the array of NAND memory cells.

In Example 38, the subject matter of any of Examples 31-37 includes,means for programming a fourth portion of the received data item intothe array at a fourth page line of the multiple page lines and at afourth plane of the multiple planes.

In Example 39, the subject matter of any of Examples 31-38, wherein thefirst portion, the second portion and the third portion compriseindividual bits within the received data.

In Example 40, the subject matter of any of Examples 31-39, wherein thethird page line and third plane are greater than the second page lineand second plane, and the second page line and second plane are greaterthan the first page line and first plane.

Example 41 is a NAND memory device comprising: an array of NAND memorycells organized into multiple planes and addressable by multiple pagelines; and a controller configured to perform operations comprising:storing a received data item in memory cells of the NAND array such thata first portion, second portion and third portion of the data item arestored in memory cells in the array such that are on different pagelines and different planes with respect to each other; calculating aparity value for the received data item using the first portion, secondportion, and third portion; assigning the parity value for the receiveddata item into a first position of a parity cluster of multiple parityclusters; and calculating a compressed parity value based upon theparity value and a second parity value of a second parity cluster of themultiple parity clusters.

In Example 42, the subject matter of Example 41, wherein the operationsof calculating the compressed parity value based upon the parity valueand the second parity value of the second parity cluster comprisesselecting the second parity value from the second parity cluster basedupon a relative position of the second parity value in the second paritycluster matching the relative position of the parity value in the firstparity cluster.

In Example 43, the subject matter of any of Examples 41-42, wherein theparity value is stored in a block of the NAND memory cells.

In Example 44, the subject matter of any of Examples 42-43, wherein theoperations comprise storing the compressed parity value in a block ofthe NAND memory cells.

In Example 45, the subject matter of any of Examples 43-44, wherein theoperations comprise overwriting the parity value with the compressedparity values.

In Example 46, the subject matter of any of Examples 41-45, wherein theoperations comprise: calculating the second parity value based uponfirst, second, and third portions of a second data item; receiving anindication that a first portion of the data item read from the array ofNAND memory cells failed an Error Correction Code check; recovering thefirst portion using the compressed parity value, the second and thirdportions of the data item, and the first, second, and third portions ofthe second data item.

In Example 47, the subject matter of any of Examples 41-46, wherein theoperations of calculating the compressed parity value comprises applyingan XOR operation to the parity value and the second parity value.

In Example 48, the subject matter of any of Examples 41-47, wherein theoperations of calculating the parity value for the received data itemusing the first portion, second portion, and third portion comprisesapplying an XOR operator to the first portion, second portion, and thirdportion.

Example 49 is a machine-readable medium, comprising instructions, whichwhen executed by a machine, cause the machine to perform operationscomprising: storing a received data item in memory cells of a NAND arraysuch that a first portion, second portion and third portion of the dataitem are stored in memory cells in the array that they are on differentpage lines and different planes with respect to each other; calculatinga parity value for the received data item using the first portion,second portion, and third portion; assigning the parity value for thereceived data item into a first position of a parity cluster of multipleparity clusters; and calculating a compressed parity value based uponthe parity value and a second parity value of a second parity cluster ofthe multiple parity clusters.

In Example 50, the subject matter of Example 49, wherein the operationsof calculating the compressed parity value based upon the parity valueand the second parity value of the second parity cluster comprisesselecting the second parity value from the second parity cluster basedupon a relative position of the second parity value in the second paritycluster matching the relative position of the parity value in the firstparity cluster.

In Example 51, the subject matter of any of Examples 49-50, wherein theparity value is stored in a block of the NAND memory cells.

In Example 52, the subject matter of any of Examples 50-51, wherein theoperations further comprise storing the compressed parity value in ablock of the NAND memory cells.

In Example 53, the subject matter of any of Examples 51-52, wherein theoperations further comprise overwriting the parity value with thecompressed parity values.

In Example 54, the subject matter of any of Examples 49-53, wherein theoperations further comprise: calculating the second parity value basedupon first, second, and third portions of a second data item; receivingan indication that a first portion of the data item read from the arrayof NAND memory cells failed an Error Correction Code check; recoveringthe first portion using the compressed parity value, the second andthird portions of the data item, and the first, second, and thirdportions of the second data item.

In Example 55, the subject matter of any of Examples 49-54, wherein theoperations of calculating the compressed parity value comprises applyingan XOR operation to the parity value and the second parity value.

In Example 56, the subject matter of any of Examples 49-55, wherein theoperations of calculating the parity value for the received data itemusing the first portion, second portion, and third portion comprisesapplying an XOR operator to the first portion, second portion, and thirdportion.

Example 57 is a method of storing data on a NAND device that includes,an array of NAND memory cells organized into multiple planes andaddressable by multiple page lines, the method comprising: storing areceived data item in memory cells of a NAND array such that a firstportion, second portion and third portion of the data item are stored inmemory cells in the array that they are on different page lines anddifferent planes with respect to each other; calculating a parity valuefor the received data item using the first portion, second portion, andthird portion; assigning the parity value for the received data iteminto a first position of a parity cluster of multiple parity clusters;and calculating a compressed parity value based upon the parity valueand a second parity value of a second parity cluster of the multipleparity clusters.

In Example 58, the subject matter of Example 57, wherein calculating thecompressed parity value based upon the parity value and the secondparity value of the second parity cluster comprises selecting the secondparity value from the second parity cluster based upon a relativeposition of the second parity value in the second parity clustermatching the relative position of the parity value in the first paritycluster.

In Example 59, the subject matter of any of Examples 57-58, wherein theparity value is stored in a block of the NAND memory cells.

In Example 60, the subject matter of any of Examples 58-59 includes,storing the compressed parity value in a block of the NAND memory cells.

In Example 61, the subject matter of any of Examples 59-60 includes,overwriting the parity value with the compressed parity values.

In Example 62, the subject matter of any of Examples 57-61 includes,calculating the second parity value based upon first, second, and thirdportions of a second data item; receiving an indication that a firstportion of the data item read from the array of NAND memory cells failedan Error Correction Code check; recovering the first portion using thecompressed parity value, the second and third portions of the data item,and the first, second, and third portions of the second data item.

In Example 63, the subject matter of any of Examples 57-62, whereincalculating the compressed parity value comprises applying an XORoperation to the parity value and the second parity value.

In Example 64, the subject matter of any of Examples 57-63, whereincalculating the parity value for the received data item using the firstportion, second portion, and third portion comprises applying an XORoperator to the first portion, second portion, and third portion.

Example 65 is a NAND memory device comprising: an array of NAND memorycells organized into multiple planes and addressable by multiple pagelines; and a controller configured to perform operations comprising:means for storing a received data item in memory cells of a NAND arraysuch that a first portion, second portion and third portion of the dataitem are stored in memory cells in the array that they are on differentpage lines and different planes with respect to each other; means forcalculating a parity value for the received data item using the firstportion, second portion, and third portion; means for assigning theparity value for the received data item into a first position of aparity cluster of multiple parity clusters; and means for calculating acompressed parity value based upon the parity value and a second parityvalue of a second parity cluster of the multiple parity clusters.

In Example 66, the subject matter of Example 65, wherein the means forcalculating the compressed parity value based upon the parity value andthe second parity value of the second parity cluster comprises means forselecting the second parity value from the second parity cluster basedupon a relative position of the second parity value in the second paritycluster matching the relative position of the parity value in the firstparity cluster.

In Example 67, the subject matter of any of Examples 65-66, wherein theparity value is stored in a block of the NAND memory cells.

In Example 68, the subject matter of any of Examples 66-67 includes,means for storing the compressed parity value in a block of the NANDmemory cells.

In Example 69, the subject matter of any of Examples 67-68 includes,means for overwriting the parity value with the compressed parityvalues.

In Example 70, the subject matter of any of Examples 65-69 includes,means for calculating the second parity value based upon first, second,and third portions of a second data item; means for receiving anindication that a first portion of the data item read from the array ofNAND memory cells failed an Error Correction Code check; and means forrecovering the first portion using the compressed parity value, thesecond and third portions of the data item, and the first, second, andthird portions of the second data item.

In Example 71, the subject matter of any of Examples 65-70, wherein themeans for calculating the compressed parity value comprises means forapplying an XOR operation to the parity value and the second parityvalue.

In Example 72, the subject matter of any of Examples 65-71, wherein themeans for calculating the parity value for the received data item usingthe first portion, second portion, and third portion comprises means forapplying an XOR operator to the first portion, second portion, and thirdportion.

Example 73 is at least one machine-readable medium includinginstructions that, when executed by processing circuitry, cause theprocessing circuitry to perform operations to implement of any ofExamples 1-72.

Example 74 is an apparatus comprising means to implement any of Examples1-72.

Example 75 is a system to implement any of Examples 1-72.

Example 76 is a method to implement any of Examples 1-72.

1. A NAND memory device comprising: an array of NAND memory cellsorganized into multiple planes and addressable by multiple page lines;and a controller configured to perform operations comprising:programming a first portion of a received data item into the array at afirst page line of the multiple page lines and at a first plane of themultiple planes; programming a second portion of the received data iteminto the array at a second page line of the multiple page lines and at asecond plane of the multiple planes; and programming a third portion ofthe received data item into the array at a third page line of themultiple page lines and at a third plane of the multiple planes.
 2. Thememory device of claim 1, wherein the operations comprise storing aparity value by applying an XOR operator to the first portion, secondportion, and third portion.
 3. The memory device of claim 2, wherein theoperations further comprise storing the parity value in the array ofNAND memory cells.
 4. The memory device of claim 3, wherein the parityvalue is stored in a location of the array of NAND memory cells that areconfigured as Single Level Cell (SLC) memory cells.
 5. The memory deviceof claim 3, wherein the first portion, second portion, and third portionare programmed into a location of the array of NAND memory cells thatare configured as Triple Level Cell (TLC) memory cells.
 6. The memorydevice of claim 2, wherein the operations comprise: determining that oneof the first portion, second portion, or third portion was corrupted;and recovering the one of the first portion, second portion, or thirdportion by utilizing the parity value.
 7. The memory device of claim 2,comprising: a volatile memory in communication with the controller; andwherein the operations further comprise: initially storing the parityvalue in the volatile memory; and moving the parity value to the arrayof NAND memory cells.
 8. The memory device of claim 1, wherein theoperations further comprise: programming a fourth portion of thereceived data item into the array at a fourth page line of the multiplepage lines and at a fourth plane of the multiple planes.
 9. The memorydevice of claim 1, wherein the first portion, the second portion and thethird portion comprise individual bits within the received data.
 10. Thememory device of claim 1, wherein the third page line and third planeare greater than the second page line and second plane, and the secondpage line and second plane are greater than the first page line andfirst plane.
 11. A method of storing data on a NAND device that includesan array of NAND memory cells organized into multiple planes andaddressable by multiple page lines, the method comprising: programming afirst portion of a received data item into the array at a first pageline of the multiple page lines and at a first plane of the multipleplanes; programming a second portion of the received data item into thearray at a second page line of the multiple page lines and at a secondplane of the multiple planes; and programming a third portion of thereceived data item into the array at a third page line of the multiplepage lines and at a third plane of the multiple planes.
 12. The methodof claim 11, further comprising storing a parity value by applying anXOR operator to the first portion, second portion, and third portion.13. The method of claim 12, further comprising storing the parity valuein the array of NAND memory cells.
 14. The memory device of claim 13,wherein the parity value is stored in a location of the array of NANDmemory cells that are configured as Single Level Cell (SLC) memorycells.
 15. The memory device of claim 13, wherein the first portion,second portion, and third portion are programmed into a location of thearray of NAND memory cells that are configured as Triple Level Cell(TLC) memory cells.
 16. The memory device of claim 12, furthercomprising: determining that one of the first portion, second portion,or third portion was corrupted; and recovering the one of the firstportion, second portion, or third portion by utilizing the parity value.17. The memory device of claim 12, further comprising: initially storingthe parity value in a volatile memory; and moving the parity value tothe array of NAND memory cells.
 18. The memory device of claim 11,further comprising: programming a fourth portion of the received dataitem into the array at a fourth page line of the multiple page lines andat a fourth plane of the multiple planes.
 19. The memory device of claim11, wherein the first portion, the second portion and the third portioncomprise individual bits within the received data.
 20. The memory deviceof claim 11, wherein the third page line and third plane are greaterthan the second page line and second plane, and the second page line andsecond plane are greater than the first page line and first plane.